Method to produce a thermoplastic wear resistant foil

ABSTRACT

A method to produce a wear resistant foil, including providing a first foil including a first thermoplastic material, applying wear resistant particles on the first foil, applying a second foil including a second thermoplastic material on the first foil, and adhering the first foil and the second foil to each other to form a wear resistant foil.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/790,774, filed on Jul. 2, 2015, now U.S. Pat. No. 10,059,084, whichclaims priority to Swedish Application Nos. 1550455-8, filed on Apr. 16,2015, 1450895-6, filed on Jul. 16, 2014, and 1450894-9, filed on Jul.16, 2014. The entire contents of each of U.S. application Ser. No.14/790,774 and Swedish Application Nos. 1550455-8, 1450895-6, and1450894-9 are hereby incorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to a method to produce a thermoplasticwear resistant foil, a method to produce a building panel including sucha thermoplastic wear resistant foil, and a building panel.

TECHNICAL BACKGROUND

In recent years, so-called Luxury Vinyl Tiles and Planks (LVT) havegained increasing success. These types of floor panels usually comprisea thermoplastic core, a thermoplastic décor layer arranged on the core,a transparent wear layer on the décor layer, and a coating applied onthe wear layer. The thermoplastic material is often PVC. The wear layeris conventionally a PVC foil, for example, having a thickness of 0.2-0.7mm. The coating applied on the wear layer is conventionally a UV curingpolyurethane coating. The wear layer together with the coating providesthe wear resistance of the floor panel and protects the décor layer.

However, when subjecting floor panels to wear, it has been shown thatthe coating and the wear layer are relatively easily worn down, or atleast worn such that the appearance of the wear layer is affected, suchas having scratches and/or not being transparent any longer. Compared toa conventional laminate floor panel, the wear resistance of a LVT floorpanel is inferior. However, LVT floors offer several advantages over,for example, laminate floors, such as deep embossing, dimensionalstability related to humidity, moisture resistance and sound absorbingproperties.

It is therefore desirable to provide a LVT product having improved wearresistance. It is also desirable to simplify the build up of LVTproduct.

It is known from US 2008/0063844 to apply a surface coating includingaluminum oxide on a resilient floor covering. The coating is a wetcoating.

WO 2013/079950 discloses an anti-skid floor covering comprising at leasttwo transparent polymer layers, wherein particles of an aggregatematerial having an average particle size of between about 0.05 mm toabout 0.8 mm are located between and/or within the two or more polymerlayers. The particles improve the slip resistance of the floor covering.

SUMMARY

It is an object of at least embodiments of the present disclosure toprovide an improvement over the above described techniques and knownart.

A further object of at least embodiments of the present disclosure is toimprove the wear resistance of LVT floorings.

A further object of at least embodiments of the present disclosure is tosimplify the buildup of LVT floorings.

At least some of these and other objects and advantages that will beapparent from the description have been achieved by a method to producea wear resistant foil according to a first aspect. The method includesproviding a first foil comprising a first thermoplastic material,applying a second foil comprising a second thermoplastic material on thefirst foil, applying wear resistant particles on the first foil and/oron the second foil prior to applying the second foil on the first foil,and adhering the first foil and to the second foil with the wearresistant particles there between for forming a wear resistant foil.

The first and the second foil may comprise different thermoplasticmaterial, or may comprise thermoplastic material of the same type.

The wear resistant particles may be applied on the first foil.

The first and the second foil may be adhered by pressing the first foiland the second foil together.

An advantage of at least embodiments of the present disclosure is that awear resistant foil having improved wear resistance is provided. Byincluding wear resistant particles in the wear resistant foil, the wearresistant particles provide additional wear resistance to thethermoplastic materials of the first and the second foil. The wearresistance of the foil is improved compared to a conventional wear layerof LVT products.

Furthermore, conventional coatings, for example a UV curablepolyurethane (PU) coating conventionally applied on the wear layer, maybe replaced by using the wear resistant foil according to the disclosureinstead. A conventional coating step may be replaced by arranging asingle foil. Thereby, the production process is simplified and thenumber of steps in the production process is reduced by arranging a wearresistant foil having improved wear resistant properties instead ofseveral layers or coatings.

By using different thermoplastic material in the first and the secondfoil, it is possible to benefit from different thermoplastic materialhaving different properties. The desired properties of the material ofthe first foil may differ from the desired properties of the secondfoil. For the second foil, properties such as stain resistance andscratch resistance are important, and the material of the second foilcan be chosen to match these criteria. Usually, suitable thermoplasticmaterial for the second foil may be more expensive compared tothermoplastic material used as, for example, in printed film or as corematerial. By only using such thermoplastic material in the second foil,the cost of the wear resistant foil can be controlled. Further, thesecond foil can have a layer thickness being less than a layer thicknessof the first foil. By choosing different thermoplastic materials for thefirst and second foil, the thermoplastic materials can be used in anefficient and cost effective manner. By adjusting the layer thickness ofthe first and second foil, the materials can be used in an even moreefficient manner.

The object of the wear resistant particles is to provide wear resistanceof the foil when being worn, not to provide slip resistance.

The wear resistant foil is preferably transparent, or at leastsubstantially transparent, for example, having a light transmittanceindex exceeding 80%, preferably exceeding 90%. Thereby, any decorativelayer or decorative print is visible through the wear resistant foil.Preferably, the wear resistant foil does not influence of the impressionof any decorative layer or decorative print arranged beneath the wearresistant foil. The wear resistant foil is preferably non-pigmented.

The wear resistant particles may be enclosed by the first and the secondfoil after being adhered to each other. The wear resistant particles maybe encapsulated by the second foil. Preferably, the wear resistantparticles do not protrude from a surface of the second foil beingopposite the first foil. If the wear resistant particles protrude beyondthe surface of the second foil, the wear resistance foil will cause wearon items placed on the wear resistance foil. For example, when the wearresistant foil is used as a top surface of a flooring, protruding wearresistant particles will cause wear on socks, shoes, etc. Further,protruding wear resistant particles would cause a rough and/or harshsurface of the wear resistant foil, as provided by a slip resistantsurface. The aim of the wear resistant particles enclosed by the foilsis to provide wear resistance when the second foil is worn, not toprovide slip resistance.

The first thermoplastic material may be or comprise polyvinyl chloride(PVC).

The second thermoplastic material may be or comprise polyurethane (PU).By arranging a second foil comprising polyurethane, no additionalpolyurethane containing coating has to be provided on top of the wearresistant foil. Thereby, the layered structure of a LVT product may besimplified. Furthermore, compared to for example a conventional wearlayer substantially consisting of PVC, a wear resistant foil comprisingan upper portion of polyurethane (PU) obtains improved chemicalresistance. Its scuff resistance and micro scratch resistance are alsoimproved. An upper layer of polyurethane (PU) also provides improvedresistance against black heel marks. An additional advantage is thatcurable polyurethane, such as UV curable polyurethane, shrinks whencuring. By pressing a thermoplastic polyurethane (PU) material, no or atleast reduced shrinking occurs.

The first foil may substantially consist of the thermoplastic material,preferably polyvinyl chloride, and optionally additives. Additives maybe plasticizers, stabilizers, lubricants, degassing agents, couplingagents, compatibilizers, crosslinking agents, etc.

The first foil may be a decorative foil. The first foil may be printed,for example by digital printing, direct printing, rotogravure printing,etc.

The second foil may substantially consist of the thermoplastic material,preferably polyurethane, and optionally additives. Additives may beplasticizers, stabilizers, lubricants, degassing agents, couplingagents, compatibilizers, crosslinking agents, etc.

In one embodiment, the first thermoplastic material may be or comprisepolyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene(PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate(PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

In one embodiment, the second thermoplastic material may be or comprisepolyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene(PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate(PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

The wear resistant particles may preferably comprise aluminum oxide. Thewear resistant particles may comprise aluminum oxide such as corundum,carborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics, or a combination thereof.

The wear resistant particles may have an average particle size of lessthan 45 μm.

The wear resistant particles may have a refractive index similar to therefractive index of the second foil. The wear resistant particles mayhave a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

A thickness of the second foil may be less than 75 μm, for example, suchas about 50 μm, after the wear resistant foil has been formed, such asafter pressing.

The wear resistant particles may have an average particle size beingless than the thickness of the second foil. The wear resistant particlesmay have an average particle size being larger than the thickness of thesecond foil. However, during pressing, the wear resistant particles arepressed into the first foil such that the wear resistant particles donot protrude beyond an upper surface of the second foil after pressing,although the wear resistant particles having an average particle sizeexceeding the thickness of the second foil.

The ratio between the average particle size of the wear resistantparticles and the thickness of the second foil may be less than 1.5:1.

The thickness of the second foil may be less than the thickness of thefirst foil.

The method may further comprise applying scratch resistant particles onthe second foil and/or the first foil. The scratch resistant particlesmay be or comprise nano-sized silica particles, preferably fused silicaparticles. The scratch resistant particles may be or comprise aluminumoxide.

Pressing the first and second foils together may comprise calenderingthe first and the second foil together.

The second foil may be formed by an extrusion process, such as extrusioncoating or extrusion lamination, preferably in connection with formingthe wear resistant foil. The first foil may be formed by an extrusionprocess such as extrusion coating or extrusion coating.

According to a second aspect, a method of forming a building panel isprovided. The method comprises applying a wear resistant foil producedaccording to the first aspect on a core, and adhering the wear resistantfoil to the core for forming a building panel.

The wear resistant foil may be adhered to the core by pressing the wearresistant foil and the core together.

The core may be provided with a decorative layer. The core may beprovided with a print on a surface of the core. The wear resistant foilis arranged on the decorative layer, or on the print.

The core may comprise a third thermoplastic material. The core may be athermoplastic core, a WPC (Wood Plastic Composite), etc. The thirdthermoplastic material may be or comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polyvinyl butyral, or a combination thereof. The core maybe provided with several layers. The core may be foamed.

According to a third aspect, a method to produce a building panel isprovided. The method includes providing a core, applying a first foilcomprising a first thermoplastic material on the core, applying a secondfoil comprising a second thermoplastic material on the first foil,applying wear resistant particles on the first foil and/or on the secondfoil prior to applying the second foil on the first foil, and adheringthe core, the first foil, and the second foil to each other to form abuilding panel.

The first and the second foil may comprise different thermoplasticmaterial, or may comprise thermoplastic material of the same type.

In one embodiment, the wear resistant foil is produced in connectionwith when forming the building panel. The first and second foil may belaminated together when laminating any other layer, for example adecorative layer, a balancing layer, etc., to the core.

The wear resistant particles may be applied on the first foil.

The core, the first foil and the second foil may be adhered to eachother by pressing the core, the first foil and the second foil togetherto form the building panel.

An advantage of at least embodiments of the present disclosure is that awear resistant foil having improved wear resistance is provided. Byincluding wear resistant particles in the wear resistant foil, the wearresistant particles provide additional wear resistance to thethermoplastic materials of the first and the second foil. The wearresistance of the foil is improved compared to a conventional wear layerof LVT products.

Furthermore, conventional coatings, for example a UV curablepolyurethane (PU) coating conventionally applied on the wear layer, maybe replaced by using the wear resistant foil according to the disclosureinstead. A conventional coating step may be replaced by arranging asingle foil. Thereby, the production process is simplified and thenumber of steps in the production process is reduced by arranging a wearresistant foil having improved wear resistant properties instead ofseveral layers or coatings.

By using different thermoplastic material in the first and the secondfoil, it is possible to benefit from different thermoplastic materialhaving different properties. The desired properties of the material ofthe first foil may differ from the desired properties of the secondfoil. For the second foil, properties such as stain resistance andscratch resistance are important, and the material of the second foilcan be chosen to match these criteria. Usually, suitable thermoplasticmaterial for the second foil may be more expensive compared tothermoplastic material used as, for example, in printed film or as corematerial. By only using such thermoplastic material in the second foil,the cost of the wear resistant foil can be controlled. Further, thesecond foil can have a layer thickness being less a layer thickness ofthe first foil. By choosing different thermoplastic materials for thefirst and second foil, the thermoplastic materials can be used in anefficient and cost effective manner. By adjusting the layer thickness ofthe first and second foil, the materials can be used in an even moreefficient manner.

The object of the wear resistant particles is to provide wear resistanceof the foil when being worn, not to provide slip resistance.

The wear resistant foil is preferably transparent, or at leastsubstantially transparent, for example, having a light transmittanceindex exceeding 80%, preferably exceeding 90%.

Thereby, any decorative layer or decorative print is visible through thewear resistant foil. Preferably, the wear resistant foil does notinfluence the impression of any decorative layer or decorative printarranged beneath the wear resistant foil. The wear resistant foil ispreferably non-pigmented.

The wear resistant particles may be enclosed by the first and the secondfoil after being adhered to each other. The wear resistant particles maybe encapsulated by the second foil. Preferably, the wear resistantparticles do not protrude from a surface of the second foil beingopposite the first foil. If the wear resistant particles protrude beyondthe surface of the second foil, the wear resistance foil will cause wearon items placed on the wear resistance foil. For example, when the wearresistant foil is used as a top surface of a flooring, protruding wearresistant particles will cause wear on socks, shoes, etc. Further,protruding wear resistant particles would cause a rough and/or harshsurface of the wear resistant foil, as provided by a slip resistantsurface. The aim of the wear resistant particles enclosed by the foilsis to provide wear resistance when the second foil is worn, not toprovide slip resistance.

The first thermoplastic material may be or comprise polyvinyl chloride(PVC).

The second thermoplastic material may be or comprise polyurethane (PU).By arranging a second foil comprising polyurethane, no additionalpolyurethane containing coating has to be provided on top of the wearresistant foil. Thereby, the layered structure of a LVT product may besimplified. Furthermore, compared to for example a conventional wearlayer substantially consisting of PVC, a wear resistant foil comprisingan upper portion of polyurethane (PU) obtains improved chemicalresistance. Its scuff resistance and micro scratch resistance are alsoimproved. An upper layer of polyurethane (PU) also provides improvedresistance against black heel marks. An additional advantage is thatcurable polyurethane, such as UV curable polyurethane, shrinks whencuring. By pressing a thermoplastic polyurethane (PU) material, no, orat least reduced, such shrinking occurs.

The first foil may substantially consist of the thermoplastic material,preferably polyvinyl chloride, and optionally additives. Additives maybe plasticizers, stabilizers, lubricants, degassing agents, couplingagents, compatibilizers, crosslinking agents, etc.

The first foil may be a decorative foil. The first foil may be printed,for example by digital printing, direct printing, rotogravure printing,etc.

The second foil may substantially consist of the thermoplastic material,preferably polyurethane, and optionally additives. Additives may beplasticizers, stabilizers, lubricants, degassing agents, couplingagents, compatibilizers, crosslinking agents, etc.

In one embodiment, the first thermoplastic material may be or comprisepolyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene(PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate(PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

In one embodiment, the second thermoplastic material may be or comprisepolyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene(PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate(PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

The wear resistant particles may preferably comprise aluminum oxide. Thewear resistant particles may comprise aluminum oxide such as corundum,carborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics, or a combination thereof.

The wear resistant particles may have an average particle size of lessthan 45 μm.

The wear resistant particles may have a refractive index similar to therefractive index of the second foil. The wear resistant particles mayhave a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

A thickness of the second foil may be less than 75 μm, for example, suchas about 50 μm, after the wear resistant foil has been formed, such asafter pressing.

The wear resistant particles may have an average particle size beingless than the thickness of the second foil. The wear resistant particlesmay have an average particle size being larger than the thickness of thesecond foil. However, during pressing, the wear resistant particles arepressed into the first foil such that the wear resistant particles donot protrude beyond an upper surface of the second foil after pressing,although the wear resistant particles having an average particle sizeexceeding the thickness of the second foil.

The ratio between the size of the wear resistant particles and thethickness of the second foil may be less than 1.5:1.

The thickness of the second foil may be less than the thickness of thefirst foil.

The method may further comprise applying scratch resistant particles onthe second foil and/or the first foil. The scratch resistant particlesmay be or comprise nano-sized silica particles, preferably fused silicaparticles. The scratch resistant particles may be or comprise aluminumoxide.

Pressing the core, the first foil and the second foil together maycomprise calendering the core, first and the second foil together.

The second foil may be formed by an extrusion process, such as extrusioncoating or extrusion lamination, preferably in connection with formingthe building panel. The first foil may be formed by an extrusion processsuch as extrusion coating or extrusion coating. The core may be extrudedor pressed, such as calendered.

The building panel may be formed in a continuous process.

The core may comprise a third thermoplastic material. The core may be athermoplastic core, a WPC (Wood Plastic Composite), etc. The thirdthermoplastic material may be or comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polyvinyl butyral, or a combination thereof. The core maybe provided with several layers. The core may be foamed.

The core may be a wood-based board or a mineral board. The core may, inembodiments, be HDF, MDF, particleboard, OSB, or Wood Plastic Composite(WPC).

A decorative layer may be arranged on the core. The decorative layer maybe a thermoplastic layer. The decorative layer may be a wood powderlayer comprising a thermosetting binder and lignocellulosic orcellulosic particles. The decorative layer may be a thermoplastic layerapplied as a powder, preferably comprising a print printed into thethermoplastic material in powder form. The decorative layer may be awood veneer layer, a cork layer or a decorative paper.

In one embodiment, the first foil is arranged directly on the core. Thecore may be provided with a print, and the first foil is arranged on theprint. Alternatively, or as a complement, the first foil may be adecorative foil. The first foil may be printed, for example by digitalprinting, direct printing, rotogravure printing, etc. Preferably, theprint is provided on a surface of the first foil facing the core.

The method may further comprise applying a coating on the second foil.The coating may comprise acrylate or methacrylate monomer or acrylate ormethacrylate oligomer. The coating may be radiation curing, such as UVcuring or electron beam curing.

According to a fourth aspect, a method to produce a building panel isprovided. The method comprises providing a core, applying a second foilcomprising a second thermoplastic material on the core, applying wearresistant particles on the core and/or the second foil prior to thesecond foil is applied on the core, and adhering the core and the secondfoil together to form a building panel.

Embodiments of the fourth aspect incorporate all the advantages of theprevious aspects, which previously has been discussed, whereby theprevious discussion is applicable also for the building panel.

The wear resistant particles may be applied on the core.

The core and the second foil may be adhered by pressing the core and thesecond foil together to form the building panel.

The wear resistant particles may be enclosed by the second foil and thecore. The wear resistant particles may be encapsulated by the secondfoil.

The second thermoplastic material may be or comprise polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof.

The wear resistant particles may be aluminum oxide.

The wear resistant may have an average particle size of less than 45 μm.

The wear resistant particles may have a refractive index similar to therefractive index of the second foil. The wear resistant particles mayhave a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

The core may be a thermoplastic core, a Wood Plastic Composite (WPC), awood-based board or a mineral board. The core may be polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The core may be foamed.

The core may be provided with a decorative layer. The decorative layermay be a printed thermoplastic film, a wood veneer layer, a cork layer,a paper layer. Alternatively, a print may be printed on an upper surfaceof the core.

A thickness of the second foil may be less than 75 μm, for example, suchas about 50 μm, after the building panel has been formed.

The second foil may be formed by an extrusion process such as extrusioncoating or extrusion lamination on the core.

By the method according to the fourth aspect, a building panelcomprising a core, a wear resistant foil comprising wear resistantparticles arranged on the core and a second foil comprising athermoplastic material arranged on the wear resistant particles andattached to the core.

Embodiment of the third aspect is applicable also for the fourth aspect.

According to a fifth aspect, a building panel is provided. The buildingpanel comprises a core, a wear resistant foil arranged on a surface ofthe core, wherein the wear resistant foil comprises a first foilcomprising a first thermoplastic material and a second foil comprising asecond thermoplastic material, and wherein wear resistant particles arearranged between the first and the second foil.

Embodiments of the fifth aspect incorporate the advantages of the firstaspect, which previously has been discussed, whereby the previousdiscussion is applicable also for the building panel.

The first and the second foil may comprise different thermoplasticmaterial, or may comprise thermoplastic material of the same type.

The wear resistant particles may be enclosed by the first foil and thesecond foil. The wear resistant particles may be encapsulated by thesecond foil.

The first thermoplastic material may be or comprise polyvinyl chloride(PVC).

The second thermoplastic material may be or comprise polyurethane (PU).

The first thermoplastic material may be or comprise polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof.

The second thermoplastic material may be or comprise polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate polyvinyl butyral, polybutyleneterephthalate, or a combination thereof.

The building panel may further comprise a decorative layer arranged onthe core, wherein the wear resistant foil is arranged on the decorativelayer.

The core may comprise a third thermoplastic material.

The core may be a thermoplastic core, a WPC (Wood Plastic Composite), awood-based board, a mineral board, etc.

The third thermoplastic material may be or comprise polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polyvinyl butyral, or a combination thereof. The core maybe provided with several layers. The core may be foamed.

The core may be a wood-based board or a mineral board. The core may inembodiments be HDF, MDF, particleboard, OSB, Wood Plastic Composite(WPC). Any intermediate layer or layers may be arranged between the coreand the decorative layer, or the wear resistant foil.

The wear resistant particles may preferably comprise aluminum oxide. Thewear resistant may comprise aluminum oxide such as corundum,carborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics, or combinations thereof.

The wear resistant particles may have an average particle size of lessthan 45 μm.

The wear resistant particles may have a refractive index similar to therefractive index of the second foil. The wear resistant particles mayhave a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

A thickness of the second foil may be less than 75 μm, for example, suchas about 50 μm, after the building panel has been formed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will by way of example be described in moredetail with reference to the appended schematic drawings, which showembodiments of the present disclosure.

FIG. 1 shows a method to produce a wear resistant foil.

FIG. 2 shows a building panel.

FIG. 3 shows a method to produce a building panel.

FIG. 4A-C show embodiments of a building panel.

FIG. 5A shows a method to produce a wear resistant foil.

FIG. 5B shows a method to produce a building panel.

DETAILED DESCRIPTION

A method to produce a wear resistant foil 10 according to an embodimentwill now be described with reference to FIG. 1. FIG. 1 shows aproduction line for producing a wear resistant foil 10. A first foil 1is provided, preferably as a continuous web. The first foil 1 may alsobe cut into sheets. The first foil 1 may also be formed by an extrusionprocess in connection with forming the wear resistant foil 10.

The first foil 1 comprises a first thermoplastic material. The firstthermoplastic material may be polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.

Preferably, the first foil 1 is formed of the thermoplastic material.The first foil 1 may substantially consist of the thermoplasticmaterial, and optionally additives. Additives may be plasticizers,stabilizers, lubricants, degassing agents, coupling agents,compatibilizers, crosslinking agents, etc.

In one embodiment, the first foil 1 is a PVC foil.

The first foil 1 may have a thickness of 0.1-1 mm.

In one embodiment, the first foil 1 is a decorative foil. The first foil1 may be printed, for example by digital printing, direct printing,rotogravure, etc. The print is preferably facing away from a second foilwhen applied on the first foil 1.

As shown in FIG. 1, an applying device 3 applies, preferably scatters,wear resistant particles 4 on the first foil 1. The wear resistantparticles 4 may be aluminum oxide particles such as corundum.Alternatively, or as a complement, the wear resistant particles 4 may becarborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics, or a combination thereof.

The wear resistant particles 4 preferably have an average particle sizeof within the range of 10-200 μm, preferably within the range of 50-120μm such as within the range of 50-100 μm. The wear resistant particles 4may have an average particle size of less than 50 μm, preferably lessthan 45 μm. The wear resistant particles 4 may have a spherical shape ormay have an irregular shape. The wear resistant particles 4 may besurface treated. The wear resistant particles 4 may be silane-treatedparticles.

The wear resistant particles 4 may have a refractive index similar tothe refractive index of the second foil 2. The wear resistant particlesmay have a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

The wear resistant particles may be applied in an amount of 20-100 g/m2,preferably in an amount of 40-60 g/m2.

After the wear resistant particles 4 have been applied on the first foil1, a second foil 2 is provided and arranged on the first foil 1. Thewear resistant particles 4 are thereby encapsulated by the first foil 1and the second foil 2.

As an alternative or complement to apply the wear resistant particles 4on the first foil 1, the wear resistant particles 4 may be applied onthe second foil 2. In this embodiment, the second foil 2 with the wearresistant particles 4 is arranged on the first foil 1, or vice versa.

The second foil 2 comprises a second thermoplastic material. The secondthermoplastic material may be the same as in the first foil 1, or beingdifferent from the thermoplastic material of the first foil 1. Thesecond thermoplastic may be polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.

Preferably, the second foil 2 is formed of the thermoplastic material.The second foil 2 may substantially consist of the thermoplasticmaterial, and optionally additives. Additives may be plasticizers,stabilizers, lubricants, degassing agents, coupling agents,compatibilizers, crosslinking agents, etc.

In one embodiment, the first foil 1 is a PVC foil and the second foil 2is PU foil.

The second foil 2 may be provided as a foil produced in a separateproduction step. The second foil 2 may be provided as continuous web.

In other embodiments, the second foil 2 may be formed by an extrusionprocess such as extrusion coating or extrusion lamination the secondfoil 2 on the first foil 1, such as described with reference to FIG. 5A.

The second foil 2 may have a thickness of 0.01-1 mm, preferably asmeasured in the final product, for example, after pressing or extruding.Preferably, the second foil 2 has a thickness less than 0.5 mm, morepreferably less than 75 μm, for example, such as about 50 μm, preferablyas measured in the final product, for example, after pressing orextruding.

The first foil 1 may have a thickness exceeding the thickness of thesecond foil 2. Especially if the first foil 1 comprises PVC and thesecond foil 2 comprises PU, the first foil 1 may have a thicknessexceeding the thickness of the second foil 2.

The wear resistant particles 4 may have an average particle size beingless than the thickness of the second foil 2. However, the wearresistant particles 4 may have an average particle size being largerthan the thickness of the second foil 2. During pressing, the wearresistant particles 4 are pressed into the first foil 1 such that thewear resistant particles 4 do not protrude beyond an upper surface ofthe second foil 2 after pressing, although the wear resistant particles4 have an average particle size exceeding the thickness of the secondfoil 2.

The ratio between the size of the wear resistant particles 4 and thethickness of the second foil 2 may be less than 1.5:1.

Scratch resistant particles (not shown) may also be applied on thesecond foil 2. As an alternative or complement, scratch resistantparticles may also be applied on the first foil 1. By scratch resistantparticles are meant particles improving the scratch or scratch resistantproperties of the first and/or second foil 1, 2. The scratch resistantparticles may be applied together with the wear resistant particles 4,for example as a mix, or may be applied separately. The scratchresistant particles may be may be or comprise nano-sized silicaparticles, preferably fused silica particles. The scratch resistantparticles may be or comprise aluminum oxide.

The scratch resistant particles may be disc shaped particles, preferablyhaving a width/thickness ratio being equal or exceeding 3:1, morepreferably being equal or exceeding 5:1. Such disc-shaped particlesorientate along the surface of the foil, thereby improving the scratchresistance of the foil. The scratch resistant particles may have anaverage particle size of 1-50 μm, preferably 10-20 μm.

The first and the second foil 1, 2 are thereafter adhered to each otherto form a wear resistant foil 10 comprising the first foil 1, the secondfoil 2, and wherein at least a part of the wear resistant particles 4are arranged between the first foil 1 and the second foil 2.

The wear resistant foil 10 is preferably transparent, or at leastsubstantially transparent.

The first and the second foil 1, 2 may be adhered to each other by beingpressed together, for example, in a calendering process. As shown inFIG. 1, the first and the second foil 1, 2 are pressed in a continuouspress 5. The first and second foil may be adhered together by pressurealone, by heat and pressure, by pressure and adhesive, or by heat,pressure, and adhesive. Preferably, both pressure and heat is applied inorder to adhere the first and the second foil to each other. As analternative or a complement to a calendering process, a continuous orstatic press may also be used. The pressing operation may, for example,be a hot-hot process, a hot-cold process, etc. The pressing may be madewith an embossed press matrix or press roller, such that an embossedstructure is formed in the wear resistant foil.

Depending on the thermoplastic materials and process used, the pressureapplied may be 5-100 bar, applied for example during 5-500 seconds. Thetemperature may be 80-300° C., such as 100-250° C., such as 150-200° C.,such as 100-130° C.

By the process described above with reference to FIG. 1, a wearresistant foil 10 is formed. The wear resistant foil 10 may be formed asa continuous foil, or be cut into sheets.

As an alternative, the first and second foil 1, 2 may be adhered to eachother by an adhesive, such as hot melt.

After adhering, for example, by pressing, the layers to each other, thewear resistant particles 4 are enclosed by the first and the second foil1, 2. Preferably, the wear resistant particles 4 do not protrude beyondthe surface of the second foil 2 facing away from the first foil 1.Thereby, a wear resistant foil 10 having a smooth surface can be formed.

It is contemplated that the wear resistant foil 10 may be adhered to adecorative layer 22 as described below in the same step such that adecorative wear resistant foil is formed.

The wear resistant foil 10 may in a subsequent step be adhered to a core21 to form a building panel 20, as shown in FIG. 2. The building panel20 may be a floor panel, a wall panel, a ceiling panel, a furniturecomponent, etc.

The core 21 may comprise a third thermoplastic material. The thirdthermoplastic material may be the same as the first and/or secondthermoplastic material, or be different from the first and/or the secondmaterial.

The third thermoplastic material may comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The core 21 may be formed ofseveral layers. The core 21 may be foamed.

In one embodiment, the core 21 comprises the third thermoplasticmaterial and fillers. The fillers may comprise calcium carbonate, suchas chalk and/or limestone.

In one embodiment, the core 21 is a Wood Plastic Composite (WPC),comprising the third thermoplastic material and wood particles asfillers.

The core 21 may be provided with a decorative layer 22 arranged on anupper surface of the core 21 as shown in FIG. 2. The wear resistant foil10 is then arranged on the decorative layer 22. The decorative layer 22may be a decorative foil comprising a thermoplastic material. Thethermoplastic material of the decorative layer may be or comprisepolyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene(PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate(PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof. The decorativefoil is preferably printed, for example by direct printing, rotogravure,or digital printing.

The core 21 may also be provided with a balancing layer (not shown)arranged on a lower surface of the core 21, opposite the decorativelayer 22. The core 21 may also be provided with intermediate layer orlayers (not shown) arranged between an upper surface of the core and thedecorative 22 layer or the wear resistant foil 11.

The wear resistant foil 10 produced according to the method describedabove with reference to FIG. 1, is arranged on the decorative layer 22.The core 21, the decorative layer 22, and the wear resistant foil 10 arepressed together to form a building panel. Heat may also be applied whenapplying pressure. The core 21, the decorative layer 22 and the wearresistant foil 10 may be pressed together in continuous press, a staticpress, or in a calendering operation. The pressing may be made with anembossed press matrix or press roller, such that an embossed structureis formed in the wear resistant foil 10.

As an alternative, the wear resistant foil 10 may be adhered to the core21 by an adhesive, such as hot melt.

A coating (not shown) may be applied on the second foil 2. The coatingmay comprise acrylate or methacrylate monomer or acrylate ormethacrylate oligomer. The coating may be radiation curing, such as UVcuring or electron beam curing.

As an alternative to a separate decorative layer 22, a print may beprinted directly on the top surface of core 21. The wear resistant foil10 is thereby arranged directly on the core.

In one embodiment, the first foil 1 is a decorative layer. The firstfoil 1 may be printed, for example by digital printing, direct printing,rotogravure, etc. The wear resistant foil 10 is in this embodimentarranged directly on the core of the above described type. The wearresistant foil 10 thereby includes a decorative layer. Preferably, theprint is facing the core 21.

An embodiment of the building panel 10 comprises a core 21 comprisingPVC, a decorative foil 22 comprising PVC, a wear resistant foil 10comprising PVC in the first foil 1 and PU in the second foil 2.

In other embodiments, the core 21 may be a wood-based board or a mineralboard. The core 21 may, for example, be a HDF, MDF, particleboard,plywood, OSB, etc.

As an alternative to the decorative foil, the decorative layer 22 may beformed of a thermoplastic material applied as a powder on the core 21. Aprint may be printed in the powder thermoplastic material. Thethermoplastic material in powder form may be polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The wear resistant foil 10 isarranged on the powder layer and pressed together. The core 21 may be ofthe above described type.

Another alternative to the decorative foil is to apply a thermosettingbinder, preferably an amino resin and in powder form, andlignocellulosic or cellulosic particles for forming the decorative layer22 on the core. A print is may be printed in the powder layer, orpigments may be included. The core 21 may be of the above describedtype. The wear resistant foil 10 is arranged on the powder layer andpressed together under heat, such that the thermosetting binder of thedecorative layer is cured.

Other alternatives for forming the decorative layer are providing a woodveneer layer, a cork layer, or a paper layer for forming the decorativelayer.

The different layers, i.e., the core 21, the decorative layer 22, thewear resistant foil 10, may be provided as continuous layers or providedas sheets.

FIG. 3 shows a method to produce a building panel 10 including forming awear resistant foil 10 integrated into the production of the buildingpanel 10. The building panel 10 may be a floor panel, a wall panel, aceiling panel, a furniture component, etc.

A core 21 is provided. The core 21 may comprise a third thermoplasticmaterial. The third thermoplastic material may be the same as the firstand/or second material, or be different from the first and/or the secondmaterial.

The third thermoplastic material may comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polycarbonate,polyacrylate, methacrylate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The core 21 may be formed ofseveral layers. The core 21 may be foamed. The core 21 may be providedas a board or as a continuous material.

In one embodiment, the core 21 comprises the third thermoplasticmaterial and fillers. The fillers may comprise calcium carbonate, suchas chalk and/or limestone, or sand.

In one embodiment, the core 21 is a Wood Plastic Composite (WPC),comprising the third thermoplastic material and wood particles asfillers.

The core 21 may be provided with a decorative layer 22 arranged on anupper surface of the core 21. The wear resistant foil 10 is thenarranged on the decorative layer 22. The decorative layer 22 may be adecorative foil comprising a thermoplastic material. The thermoplasticmaterial of the decorative layer may be or comprise polyvinyl chloride(PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene(PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The decorative foil ispreferably printed, for example by direct printing, rotogravure, ordigital printing. The decorative layer may be a wood veneer layer, acork layer, a paper layer. The decorative layer 22 may be provided as acontinuous web or as sheets.

The core 21 may also be provided with a balancing layer (not shown)arranged on a lower surface of the core 21, opposite the decorativelayer 22.

A first foil 1 is arranged on the core 21, or on the decorative layer22. The first foil 1 comprises a first thermoplastic material. The firstthermoplastic material may be polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.

Preferably, the first foil 1 is formed of the thermoplastic material.The first foil 1 may substantially consist of the thermoplasticmaterial, and optionally additives. Additives may be plasticizers,stabilizers, lubricants, degassing agents, coupling agents,compatibilizers, crosslinking agents, etc.

In one embodiment, the first foil 1 is a PVC foil.

The first foil 1 may have a thickness of 0.1-1 mm preferably as measuredin the final product, for example, after pressing or extruding.

The first foil 1 may be provided as a continuous web. The first foil 1may also be cut into sheets. The first foil 1 may also be formed by anextrusion process, preferably in connection with forming the buildingpanel.

As shown in FIG. 3, an applying device 3 applies, preferably scatters,wear resistant particles 4 on the first foil 1. The wear resistantparticles 4 may be aluminum oxide particles, such as corundum.Alternatively, or as a complement, the wear resistant particles 4 may becarborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics, or a combination thereof. The wear resistant particles 4 maybe surface treated. The wear resistant particles 4 may be silane-treatedparticles.

The wear resistant particles 4 preferably have an average particle sizewithin the range of 10-200 μm, preferably within the range of 50-120 μm,such as 50-100 μm. The wear resistant particles 4 may have an averageparticle size of less than 50 μm, preferably less than 45 μm. The wearresistant particles 4 may have a spherical shape or an irregular shape.

The wear resistant particles 4 may have a refractive index similar tothe refractive index of the second foil 2. The wear resistant particlesmay have a refractive index of 1.4-1.7. In one embodiment, the wearresistant particle may have a refractive index of 1.4-1.9, preferably1.5-1.8, for example, 1.7-1.8. The refractive index of the wearresistant particles may not differ from the refractive index of thesecond foil more than ±20%.

The wear resistant particles may be applied in an amount of 20-100 g/m2,preferably in an amount of 40-60 g/m2.

The wear resistant particles 4 may have an average particle size beingless than the thickness of the second foil 2. However, the wearresistant particles 4 may have an average particle size being largerthan the thickness of the second foil 2. During pressing, the wearresistant particles 4 are pressed into the first foil such that the wearresistant particles do not protrude beyond an upper surface of thesecond foil 2 after pressing, although the wear resistant particles 4having an average particle size exceeding the thickness of the secondfoil.

The ratio between the size of the wear resistant particles 4 and thethickness of the second foil 2 may be less than 1.5:1.

After the wear resistant particles 4 have been applied on the first foil1, a second foil 2 is provided and arranged on the first foil 1. Thewear resistant particles 4 are thereby encapsulated between the firstfoil 1 and the second foil 2.

As an alternative or complement to apply the wear resistant particles 4on the first foil 1, the wear resistant particles 4 may be applied onthe second foil 2. In this embodiment, the second foil 2 with the wearresistant particles 4 is arranged on the first foil 1, or vice versa.

The second foil 2 comprises a second thermoplastic material. The secondthermoplastic material may be the same as in the first foil 1, or beingdifferent from the thermoplastic material of the first foil 1. Thesecond thermoplastic may be polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.

The second foil 2 may be provided as a foil produced in a separateproduction step. The second foil 2 may be provided as continuous web asshown in FIG. 3.

In other embodiments, the second foil 2 may be formed by an extrusionprocess such as extrusion coating or extrusion lamination the secondfoil 2 on the first foil 1 as described with reference to FIG. 5B.

The second foil 2 may have a thickness of 0.01-1 mm, preferably asmeasured in the final product, for example, after pressing or extruding.Preferably, the second foil 2 has a thickness less than 0.5 mm, morepreferably less than 75 μm, for example, such as about 50 μm, preferablyas measured in the final product, for example, after pressing orextruding.

Preferably, the second foil 2 is formed of the thermoplastic material.The second foil 2 may substantially consist of the thermoplasticmaterial, and optionally additives. Additives may be plasticizers,stabilizers, lubricants, degassing agents, coupling agents,compatibilizers, crosslinking agents, etc.

In one embodiment, the first foil 1 is a PVC foil and the second foil 2is PU foil.

Scratch resistant particles (not shown) may be applied on the secondfoil 2. As an alternative or complement, scratch particles may also beapplied on the first foil 1 prior to applying the second foil 2. Byscratch resistant particles are meant particles improving the scratch orscratch resistant properties of the first and/or second foil. Thescratch resistant particles may be applied together with the wearresistant particles 4, for example as a mix, or may be appliedseparately. The scratch resistant particles may be may be or comprisenano-sized silica particles, preferably fused silica particles. Thescratch resistant particles may be or comprise aluminum oxide.

The scratch resistant particles may be disc shaped particles, preferablyhaving a width/thickness ratio being equal or exceeding 3:1, morepreferably being equal or exceeding 5:1. Such disc-shaped particlesorientate along the surface of the foil, thereby improving the scratchresistance of the foil. The scratch resistant particles may have anaverage particle size of 1-50 μm, preferably 10-20 μm.

The different layers, i.e. the core 21, the decorative layer 22, thewear resistant foil 10, may be provided as continuous layers or beingcut into sheets.

The core 21, the first foil 1 and the second foil 2 are thereafteradhered to each other to form a building panel 20 comprising the core21, the first foil 1, the second foil 2, and wherein a least a portionof the wear resistant particles 4 are arranged between the first foil 1and the second foil 2. The first foil 1, the second foil 2 and the wearresistant particles 4 arranged therebetween form a wear resistant foil10 of the building panel 20.

The wear resistant foil 10 is preferably transparent, or at leastsubstantially transparent, for example, having a light transmittanceindex exceeding 80%, preferably exceeding 90%.

The core 21, the first and the second foil 1, 2 may be adhered to eachother by being pressed together in a pressing station 5. The press maybe a continuous or static press. The core 21, the first and the secondfoil 1, 2 may be calendered together. Preferably, both pressure and heatis applied in order to adhere the first and the second foil to eachother. The pressing operation may for example be made as a hot-hotprocess, a hot-cold process, etc. The pressing may be made with anembossed press matrix or press roller, such that an embossed structureis formed in the wear resistant foil 10.

Depending on the thermoplastic materials and process used, the pressureapplied may be 5-100 bar, applied for example during 5-500 seconds. Thetemperature may be 80-300° C., such as 100-250° C., such as 150-200° C.

As an alternative, the layers may be adhered to each other by anadhesive, such as hot melt.

After adhering, for example, by pressing, the layers to each other, thewear resistant particles are enclosed by the first foil, or by the firstand the second foil. Preferably, the wear resistant particles do notprotrude beyond the surface of the second foil facing away from thefirst foil. Thereby, a wear resistant foil 10 having a smooth surfacecan be formed.

A coating (not shown) may be applied on the second foil 2. The coatingmay comprise acrylate or methacrylate monomer or acrylate ormethacrylate oligomer. The coating may be radiation curing, such as UVcuring or electron beam curing.

As an alternative to a separate decorative layer 22, a print may beprinted directly on the upper surface of core 21. The wear resistantfoil 10 is thereby arranged directly on the core.

As an alternative to a separate decorative layer 22, the first foil 1 ofthe wear resistant foil 10 may be a decorative foil. The first foil 1may be printed, for example by digital printing, direct printing,rotogravure, etc. The wear resistant foil 10 is thereby arrangeddirectly on the core 21. Preferably, the print faces the core 21.

As an alternative to the decorative foil described above, the decorativelayer 22 may be formed of a thermoplastic material applied as a powderon the core. A print may be printed in the powder thermoplasticmaterial. The thermoplastic material in powder form may be polyvinylchloride (PVC), polyester, polypropylene (PP), polyethylene (PE),polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET),polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or combination thereof. The first foil 1 ofthe wear resistant foil 10 is arranged on the powder layer and pressedtogether as described above. The core 21 may be of the above describedtype.

Another alternative to the decorative foil described above is to apply athermosetting binder, preferably an amino resin and in powder form, andlignocellulosic or cellulosic particles for forming the decorative layer22 on the core 21. A print is may be printed in the powder layer, orpigments may be included. The core 21 may be of the above describedtype. The first foil 1 of the wear resistant foil 10 is arranged on thepowder layer and the powder layer and the first foil 1 are pressedtogether under heat as described above, such that the thermosettingbinder of the decorative layer is cured.

Other alternatives for forming the decorative layer 22 are providing awood veneer layer, a cork layer or a paper layer for forming thedecorative layer.

It is also contemplated that the first foil 1 may be excluded. The wearresistant particles 4 of the above described type may be applieddirectly on the core 21 of the above described type. The second foil 2of the above described type may be arranged on an upper surface of thecore 21 and on the wear resistant particles 4. The upper surface of thecore 21 may be provided with a print. Alternatively, a decorative layer22 of the above type may be arranged on the core 21. The core 21, thewear resistant particles 4, and the second foil 2 are then pressedtogether to form a building panel 20 in the above described way.

It is contemplated that the core 21 may be excluded in the embodimentsdescribed with reference to FIG. 3. By pressing together the decorativelayer 22 and the wear resistant foil 10, a decorative substrate havingwear resistant properties is provided.

In addition to the building panel 20 described above with reference toFIG. 2, building panels 20 having another structure may also be providedby the methods described above.

According to one embodiment, which is shown in FIG. 4A, building panel10 comprising a core 21 of the above described type and a wear resistantfoil 10 manufactured according to the embodiment described withreference to FIG. 1. Alternatively, the building panel 10 ismanufactured according to the embodiment described with reference toFIG. 3 wherein the decorative layer 22 is excluded. An upper surface ofthe core 21 may be provided with a print 23, for example printed by forexample by digital printing, direct printing or rotogravure. The wearresistant foil 10 is arranged directly on the core 21.

According to one embodiment, which is shown in FIG. 4B, a building panel10 comprising a core 21 of the above described type and a wear resistantfoil 10 manufactured according to the embodiment described withreference to FIG. 1. Alternatively, the building panel 10 ismanufactured according to the embodiment described with reference toFIG. 3, wherein the decorative layer 22 is excluded. The first foil 1 ofthe wear resistant foil 10 may be a decorative foil. The first foil 1may be provided with a print 23, for example printed by digitalprinting, direct printing or rotogravure. The wear resistant foil 10 isarranged directly on the core 21.

It is contemplated that in one embodiment, the first foil 1 may beexcluded in the embodiment described above with reference to FIG. 3.According to this embodiment, which is shown in FIG. 4C, the wearresistant particles 4 are applied directly on a core 21 of the abovedescribed type. An upper surface of the core 21 may be provided with aprint 23, for example printed by digital printing, direct printing orrotogravure. Alternatively, the core 21 may be provided with adecorative layer 22 of the above described type, for example, a printedthermoplastic foil, a wood veneer layer, a cork layer, a paper layer,etc. A second foil 2 of the above described type is applied directly onthe wear resistant particles 4 of the above described type and the uppersurface of the core 21. A building panel 20 including a wear resistantfoil 10′ formed by the wear resistant particles 4 and the second foil 2is thereby formed.

In all embodiments, the second thermoplastic material of the above typemay be applied in an extrusion process, which is shown in FIGS. 5A-B. InFIG. 5A, a first foil 1 is provided. The first foil 1 is of the typedescribed above with reference to FIGS. 1, 2, 3, 4A-B. In the embodimentshown FIG. 5A, the wear resistant particles 4 of the above describedtype are applied on the first foil 1 by the applying device 3. Thesecond thermoplastic material 5 is preferably provided as granulates.The second thermoplastic material 5 is applied on the first foil 1 inmolten form by an extruder 8. For example, the second thermoplasticmaterial 5 is applied on the first foil 1 by an extrusion process suchas extrusion lamination or extrusion coating. The second thermoplasticmaterial 5 is applied after the wear resistant particles 4 have beenapplied. Thereby, a wear resistant foil 10 has been produced.

The method to produce a wear resistant foil 10 by using an extrusiontechnique as described above with reference to FIG. 5A is alsoapplicable when forming a building panel corresponding to the embodimentshown in FIG. 4A-B, which is shown in FIG. 5B.

In FIG. 5B, a first foil 1 and a core 21 are provided. The first foil 1and the core 21 are of the type described above with reference to FIGS.3 and 4A-B. In the embodiment shown FIG. 5B, the wear resistantparticles 4 of the above described type are applied on the first foil 1by an applying device 3. The second thermoplastic material 5 ispreferably provided as granulates. The second thermoplastic material 5is applied on the first foil 1 in molten form by an extruder 8. Forexample, the second thermoplastic material 5 is applied on the firstfoil 1 by an extrusion process such as extrusion lamination or extrusioncoating. The second thermoplastic material 5 is applied after the wearresistant particles 4 have been applied.

The core 21, the first foil 1 provided with the wear resistant particles4 and the second thermoplastic material 5 are adhered together forforming a building panel 20, for example, by pressing, such ascalendaring, for example, by calendering rolls 6, as shown in FIG. 5B.Alternatively, the layers may be adhered to each other by means of anadhesive such as hot melt.

It is also contemplated that the co-extruding may be used to form thewear resistant foil. The first foil comprising the first thermoplasticmaterial and a second foil comprising the second thermoplastic materialmay be formed by co-extruding the first and the second foil. The wearresistant particles may be mixed with the second thermoplastic material,or applied separately on the first and/or the second foil.

Any of the above described building panels 10 may be provided with amechanical locking system. The mechanical locking system may be of thetype described in WO 2007/015669, WO 2008/004960, WO 2009/116926, or WO2010/087752, the entire contents of each is expressly incorporated byreference herein.

In the embodiments above, the wear resistant foil 10 is described asincluding the first foil 1 and the second foil 2. However, afterpressing, the boundaries between the first and the second foil 1, 2 maybe less distinct, such that in some embodiments it may be difficult todistinguish the first foil 1 from the second foil 2. At least a part ofthe wear resistant particles are 4 located intermediate the first andthe second foil 1, 2. A part of the wear resistant particles 4 may belocated within the second foil 2.

It is contemplated that the first foil 1 may be formed of a powderlayer, for example, comprising the first thermoplastic material of theabove described type and optionally filler such as wood particles,calcium carbonate, sand, etc.

It is contemplated that there are numerous modifications of theembodiments described herein, which are still within the scope of thedisclosure. For example, it is contemplated that more than one wearresistant foil may be arranged on a core for forming a building panel.

EXAMPLES Example 1: Comparative Example

A PVC wear layer foil with a thickness of 0.3 mm was positioned on adecorative foil with a thickness of 0.1 mm. The two foils were laminatedon to a PVC core material using a temperature of 160° C., a pressure of20 bar and a pressing time of 40 seconds. The resulting product was aLVT product. The LVT product was found to have a wear resistance of 3200revolutions as tested in a Taber abrader.

Example 2: PVC Foil on PVC Foil

A PVC wear layer foil with a thickness of 0.3 mm was positioned on adecorative foil with a thickness of 0.1 mm. On to the wear layer foil 10g/m2 Al2O3 was scattered using a scattering device. A second PVC wearlayer foil with a thickness of 0.3 mm was positioned on the scatteredAl2O3. The three foils were laminated on to a PVC core material using atemperature of 160° C., a pressure of 20 bar and a pressing time of 40seconds. The resulting product was a LVT product. The LVT product wasfound to have a wear resistance higher than 8000 revolutions as testedin a Taber abrader.

Example 3: PU Foil on PVC Foil

A PVC wear layer foil with a thickness of 0.3 mm was positioned on adecorative foil with a thickness of 0.1 mm. On to the wear layer foil 10g/m2 Al2O3 was scattered using a scattering device. A PU foil with athickness of 0.05 mm was positioned on the scattered Al2O3. The threefoils were laminated on to a PVC core material using a temperature of140° C., a pressure of 20 bar and a pressing time of 40 seconds. Theresulting product was a LVT product. The LVT product was found to have awear resistance higher than 8000 revolutions as tested in a Taberabrader.

Example 4: PU Foil on PVC Foil

A printed decorative PVC foil having a thickness of 0.08 mm was arrangedon a core comprising three layers and having a thickness of 4 mm. A PVCwear layer having a thickness of 0.25 mm was arranged on the decorativePVC foil. Wear resistant particles in form of aluminum oxide wereapplied in an amount of 40 g/m2 on the PVC wear layer. A PU foil havinga thickness of 0.05 mm was arranged on the wear resistant particles andthe PVC wear layer. The different layers were pressed together in acold-hot-cold process. The pressure applied was 10 bar. The temperaturesapplied in the cold-hot-cold process were 50° C., 140° C., and 50° C.The product was pressed at 140° C. during 4 minutes. The total pressingtime was approximately 55 minutes. The resulting product was a LVTproduct. The LVT product was found to have a wear resistance higher than8000 revolutions as tested in a Taber abrader.

The invention claimed is:
 1. A method to produce a building panel,comprising providing a core, applying a first foil comprising a firstthermoplastic material on the core, applying a second foil comprising asecond thermoplastic material on a side of the first foil opposite to aside of the first foil applied to the core, applying wear resistantparticles on the first foil and/or on the second foil prior to applyingthe second foil on the first foil, and adhering the core, the first foiland the second foil to each other to form the building panel, whereinall off the wear resistant particles do not protrude from a surface ofthe second foil opposite the first foil.
 2. The method according toclaim 1, wherein the wear resistant particles are enclosed by the firstand the second foils after the second foil is applied to the first foil.3. The method according to claim 1, wherein the first thermoplasticmaterial comprises polyvinyl chloride (PVC).
 4. The method according toclaim 1, wherein the second thermoplastic material comprisespolyurethane (PU).
 5. The method according to claim 1, wherein the firstthermoplastic material comprises polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.
 6. The method according to claim 1, wherein thesecond thermoplastic material comprises polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof.
 7. The method according toclaim 1, wherein the wear resistant particles comprise aluminum oxide.8. The method according to claim 1, wherein the wear resistant particleshave an average particle size of less than 45 μm.
 9. The methodaccording to claim 1, wherein the core, the first foil and the secondfoil are adhered to each other by pressing.
 10. The method according toclaim 9, wherein a thickness of the second foil is less than 75 μm afterpressing.
 11. The method according to claim 1, wherein the wearresistant particles are applied on the first foil.
 12. The methodaccording to claim 1, wherein the second foil is formed by an extrusionprocess.
 13. The method according to claim 1, wherein the first foil,the second foil and the wear resistant particles form a wear resistantfoil which is substantially transparent.
 14. The method according toclaim 1, wherein the core comprises a third thermoplastic material. 15.The method according to claim 14, wherein the third thermoplasticmaterial comprises polyvinyl chloride (PVC), polyester, polypropylene(PP), polyethylene (PE), polystyrene (PS), polyurethane (PU),polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.
 16. The method according to claim 1, wherein thecore is a wood-based board, a wood plastic composite (WPC), athermoplastic board or a mineral board.
 17. The method according toclaim 1, further comprising arranging a decorative layer on the core.18. A method to produce a building panel, comprising providing a core,applying a foil comprising a thermoplastic material on the core,applying wear resistant particles on the core and/or on the foil priorto the foil being applied on the core, and adhering the core and thefoil together to form a building panel, wherein all off the wearresistant particles do not protrude from a surface of the foil oppositea surface of the foil applied on the core.
 19. The method according toclaim 18, wherein the wear resistant particles are enclosed by the foiland the core.
 20. The method according to claim 18, wherein thethermoplastic material comprises polyvinyl chloride (PVC), polyester,polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane(PU), polyethylene terephthalate (PET), polyacrylate, methacrylate,polycarbonate, polyvinyl butyral, polybutylene terephthalate, or acombination thereof.
 21. The method according to claim 20, wherein thewear resistant particles have an average particle size of less than 45μm.
 22. The method according to claim 20, wherein the core and the foilare adhered to each other by pressing and a thickness of the foil isless than 75 μm after pressing.
 23. The method according to claim 20,wherein the core and the foil are adhered to each other by pressing. 24.The method according to claim 20, wherein the wear resistant particlesare applied on the core.
 25. The method according to claim 20, whereinthe foil is formed by an extrusion process.
 26. The method according toclaim 18, wherein the core is a thermoplastic core, a wood plasticcomposite (WPC), a wood-based board or a mineral board.